Sharraxaadda

The speed limit is 30mph, but there are no signs coming from Clarksville Hwy and I don't think there is one coming from Eaton's Creek. People drive in excess of 40mph down our street daily. What can be done? Can you put up a speed limit sign? I have a yard sign asking people to slow down, to no avail. We have a Metro PD officer who also lives on this street and this doesn't help either.
Thank you for your attention.